1. Field of the Invention
The present invention relates to an image holding member that holds an electrostatic image or a toner image, and an apparatus making use of such a member.
2. Related Background Art
Electrostatic images or toner images are formed by various processes. Image holding members on which the electrostatic images or toner images are carried grouped into an image holding member having a photoconductive layer, called an electrophotographic photosensitive member, and an image holding member having no photoconductive layer.
The image holding members are usually comprised of a support and an image holding layer provided thereon.
Electrophotographic photosensitive members are constituted in various embodiments based on achievement of the desired performances or depending on the types of electrophotographic processes applied. A typical electrophotographic photosensitive member includes a photosensitive member comprised of a support and a photoconductive layer formed thereon as an image holding layer, and a photosensitive member comprised of a photoconductive layer as an image holding layer and an insulating layer laminated thereon. Both of these are in wide use. The photosensitive member comprised of a support and a photoconductive layer is used in forming images by the most commonly available electrophotographic process, i.e., by charging, imagewise exposure and development, and also optionally by transfer. In regard to the photosensitive member provided with an insulating layer, this insulating layer is provided for the purposes of protecting the photoconductive layer, improving mechanical strength of the photosensitive member and improving dark-decay characteristics, or so that the photosensitive member can be applied in a specific electrophotographic process as disclosed in Japanese Patent Publication No. 42-13910.
In a specific electrophotographic process, an electrostatic image is formed on the electrophotographic photosensitive member. This electrostatic image is developed and converted into a visible image.
The image holding member having no photoconductive layer typically includes a member having an insulating layer serving as an image holding layer. Some typical uses of this image holding member are as follows:
(1) An image holding member used in the following electrophotographic process: For example, as disclosed in Japanese Patent Publications No. 32-7115, No. 32-8204 and No. 43-1559, for the purpose of improving repeated usability of electrophotographic photosensitive members, an electrostatic image formed on an electrophotographic photosensitive member is developed after it has been transferred to an image holding member having no photoconductive layer, and then the toner image is transferred to a recording medium.
(2) An image holding member used in the following electrophotographic process: Electrical signals are applied to a multi-stylus electrode to form, corresponding with the electrical signals, an electrostatic image on the surface of an image holding member having no photoconductive layer, and the electrostatic image is developed to form a visible image.
Image holding members are commonly comprised of a conductive support and an image holding layer formed thereon. As the conductive support, it is common to use an aluminum drum whose surface has been mirror-finished. The mirror finishing is a measure necessary for achieving uniform thickness of the image holding layer and uniform electrostatic properties of the support and also to prevent image quality from being lowered. The mirror finishing, however, is a cause of an increase in cost, and hence it has been sought to provide an inexpensive and highly efficient support.